Kitami Institute of Technology testing method to control germination using polymer chemistry — Aims to reduce burden on farmers

This season is generally the off-season for farming. In Hokkaido, which is cold, two-season and double cropping is particularly difficult. When the weather starts to warm up, farmers get very busy; however, in recent years, a shortage of people willing to do farmwork has become a serious problem. Hokkaido, which boasts a food self-sufficiency rate of over 200%, is no exception. If only the work could be done during the winter months... To respond to these voices, Science Portal interviewed a researcher who is trying to control germination with polymer chemistry.

"Direct seeding" of onions not progressing, production relies on labor-intensive "transplanting"

The writer visited Kitami City in the east of Hokkaido. The Okhotsk Region, which includes Kitami, is a hub of primary industries. Its fishing industry is the largest in Hokkaido, and its agriculture ranks second after the Tokachi Region. Among them, onion cultivation is flourishing, and approximately 20% of domestic shipments come from Kitami City.

Growing onions is extremely costly, I was told. Seedlings are grown in plastic greenhouses during the winter and replanted in outdoor fields in the spring. As a matter of fact, 98% of the production is through this labor-intensive "transplanting" process. It also requires a capital investment of 30 million yen, which is a barrier for new farmers.

Adding to the hardships faced by farmers is the shortage of labor. Farmers are extremely busy from spring onward. In order to cope with the increased burden, beets, which had been mostly transplanted, are switching to "direct seeding," in which the seeds are sown directly in the field. But onions and rice are more difficult, and direct seeding has not made much progress.

Controlling germination timing with polymers

Against this backdrop, Associate Professor Takeshi Namikoshi of the School of Earth, Energy and Environmental Engineering at the Kitami Institute of Technology, is conducting research to reduce the burden on farmers by making the direct seeding of onions and other crops possible. The concept is to coat seeds with a polymer to control the time to germination.

The polymer acts as a barrier to prevent moisture from reaching the seeds, so they do not germinate immediately after being sown in the field. Polymers are adjusted to soften at around 5 degrees Celsius, so they gradually collapse as temperatures rise in spring. As a result, moisture is able to reach the seed and germination occurs. In other words, all a farmer needs to do is sow the seeds in winter when temperatures are below 5 degrees Celsius, then wait for the season to turn warm and germination to begin.

It may seem like an outlandish idea, but Namikoshi explains, "Many of the seeds used today are actually coated as well. The objective for this is to make it easier for the automatic seed spreader to spread the seed evenly and to increase visibility."

Two-layer coating to realize late fall seeding

Namikoshi's aim is a leveling out of farm work across the seasons. After repeated discussions with farmers, he found that if some of the work done during the busy farming season could be shifted to the off-season, the burden and costs would be greatly reduced. His goal is to address this challenge using his knowledge of polymer chemistry.

Namikoshi is also working hard to improve the technology further. Farming at temperatures below 5 degrees Celsius is not only too cold, but if the field freezes over, the seeds cannot be sown, and the machinery may break down. To address these issues, he is testing a two-layer coating method that adds a polymer that dissolves in water at low temperatures, enabling sowing in late autumn right after harvest.

Namikoshi also has other applications in mind. He would like to make it possible to control germination in various ways, for example, by promoting germination in pumpkins, which germinate poorly in the cold, or by allowing fertilizer to take effect gradually as the polymer dissolves.

Germination rate reaches set level after repeated tests in farm fields

The idea started with feedback from farmers. Around 2016, while looking for interdisciplinary research themes, Namikoshi learned at a gathering with local farmers that the uneven distribution of farm work across the seasons was a major problem. He recalls, "I was not originally targeting only agriculture, but as a researcher working in Kitami, I thought it would be a worthwhile theme to work on."

"The number of farmers going out of business has increased, and the area planted per household is on the rise. Although the average age of Hokkaido farmers is 58, about 10 years younger than the national average, the aging of the population is certain to continue. We have to do something about it before it's too late."

There are many challenges to realization. In agriculture, yield is directly related to income, making it difficult to switch from conventional methods to new ones. To show that switching to direct seeding does not reduce yields, Namikoshi has been borrowing a section of farmland from a local farmer to carry out repeated field tests. The germination rate has risen greatly, from 40% when he first tried it in an incubator in 2022 to 64% in actual farmland cultivation in 2025. Given that the germination rate standard shown by the Ministry of Agriculture, Forestry and Fisheries to seed companies and others for onion seeds is 70%, it is fair to say that the rate is getting close to an acceptable level.

Every possible approach for early practical use

However, because most crops can only be harvested once a year, there is a limit to how many times field tests can be run. Namikoshi, who also aims to start a company, has been receiving calls from investment funds asking for "practical application within two to three years." Therefore, Namikoshi is working on another approach to demonstrate the feasibility of winter direct seeding.

"It is grass for planting on highway embankments. The quality standards are not as strict as for crops, so I want to first focus on quickly establishing the method, including raising the germination rate," says Namikoshi.

It also helped that many faculty members at Kitami Institute of Technology have strong ties to the construction industry. He says collaboration with companies has already begun. Using these kinds of strategies as well, he is working every day on both research and business planning, aiming to start a company around 2029.

Licensing business first, then in-house seed production in the future.

Still, what everyone is most curious about is practical application for Kitami's signature product, onions. When asked about the timeline, Namikoshi gave a wry smile and said, "Onions are actually quite difficult." Then he added with enthusiasm: "I want to aim for within five years, while making sure safety is guaranteed."

For now, Namikoshi plans to develop a licensing-based business, with the future goal of producing polymer-coated seeds in-house. With food security becoming an important social issue, he feels that "farmers have a strong sense of crisis about not having enough hands. It is a big opportunity to replace the old methods." Because the research started from the needs of farmers, he says he has had no trouble getting their understanding.

Will the dream that Namikoshi, who was born in the Okhotsk region, shares with local farmers end up saving Japan's dinner table? This is a story worth following.